Continuous sedimentation tank with center-pier supported sediment raking apparatus

ABSTRACT

A drive head for a center pier-supported rake structure in a sedimentation tank, featuring a peripherally overhanging top structure mounted on a turntable base, and carrying drive means for an externally toothed bull gear connected to the rake structure, and supported for rotation on the turntable base below said overhanging top structure.

United States Patent J ablon et al.

CONTINUOUS SEDIMENTATION TANK WITH CENTER-PIER SUPPORTED SEDIMENT RAKING APPARATUS Inventors: Theodore M. .lablon, Stamford, Conn.; Russell C. Raynor, South Salem, N.Y.

Assignee: Dorr-Oliver Incorporated, Stamford,

Conn.

Filed: Sept. 8, 1969 Appl. No.: 856,054

Related U.S. Application Data Continuation of Ser. No. 748,893, June 21, 1968, abandoned, which is a continuation-in-part of Set. Nov 537,170, March 24, 1966, abandoned.

us. Cl ..210/531 Int. Cl. ...B01d 21/12 Field of Search ..210/528, 531

Dec. 5, 1972 [56] References Cited UNITED STATES PATENTS 3,498,468 3/1970 Raynor ..210/528 Primary Examiner-Reuben Friedman Assistant Examiner-Frederick F. Calvetti AttorneyTheodore M. Jablon, J. Dennis Malone and Dominic M. Mezzapelle [5 7 ABSTRACT A drive head for a center pier-supported rake structure in a sedimentation tank, featuring a peripherally overhanging top structure mounted on a turntable base, and carrying drive means for an externally toothed bull gear connected to the rake structure, and supported for rotation on the turntable base below said overhanging top structure.

32 Claims, 13 Drawing Figures PKTENTED DEC 5 I97? 3. 704. 789

SHEET 1 BF 6 INVENTORS. THEODORE M. JABLON RUSSELL C. RAYNOR ATTORNEY.

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PATENTEDBEC 5 m2 SHEET 2 OF 6 INVENTORS. THEODORE M. JABLON RUSSELL C- RAYNOR BY ATTORNEY.

PATENTEDBEE 51912 3.704.789

SHEET 3 BF 6 INVENTORS. THEODORE M. JABLON RUSSELL C. RA NOR ATTORNEY.

PATENTED DEC 5 I97? 3 704 789 sum u or 6 IN VENTORS. THEODORE M. JABLON RUSSELL C. RAYNOR %adam iaflu P'ATE'N'TEDnEc 5:912

SHEET 5 BF 6 INVENTORS. THEODORE M. JABLON Y RUSSELL C. RAY/Vol? B v mam ATTORNEY PA'TE'NTEDUEB 5 m2 SHEET 6 BF 6 hm. km

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THEODORE M JA 81. ON RUSSELL 6. RA YNOR BY ATTORNEY CONTINUOUS SEDIMENTATION TANK WITH CENTER-PIER SUPPORTED SEDIMENT RAKING APPARATUS This is a Continuation of application Ser. No. 748,893 filed June 21, 1968 which in turn is a Continuation-in-Part application of application Ser. No. 537,170 filed Mar. 24, 1966, now both abandoned.

This invention relates to continuously operating sedi mentation tanks wherein the sediment conveying rake structure is supported for rotation on a center pier or the like rising from the bottom of the tank.

The invention more particularly relates to improvements in the means or drive head construction which supports and drives the rake structure, and which in turn is supported on the central base portion of the tank.

I-Ieretofore, in the drive head, it has been customary to have an internally toothed large bull gear fixed to the top end of the center cage of the rake structure, which center cage surrounds the pier. This bull gear has an outer rim portion fixed to the center cage, and an inwardly overhanging internally toothed portion concentrically supported on an annular vertical thrust bearing located in an annular oil trough provided on a'stationary frame structure or turntable base. Thus, with the bearing surrounding the internally tooth portion, the diameter of the bearing always had to be larger than the pitch diameter of the gear, so that with any desired increase in the size of the gear the diameter of the bearing also had to be increased.

The internally toothed bull gear was driven by a motorized pinion drive unit mounted on the turntable base, in a position located within the area surrounded by the gear, and the available working platform space on the drive head was limited substantially to an area corresponding to the area occupied by the gear.

While such a drive head construction has been generally satisfactory over the years, nevertheless with increasing tank sizes, the increase in the diameter of the bull gear would in turn compel an increase in the diameter of the annular thrust bearing to an uneconomical size. Moreover, the internally toothed conventional bull gear is inaccessible, and difficult to replace, inasmuch as the gear member itself provides the suspension element for the rake structure.

It is among the objects of this invention to provide an improved drive head of great design flexibility, and which avoids the foregoing limitations of the conventional construction. Accordingly, it is among the objects to render the parts of the mechanism especially the bull gear readily accessible as well as detachable without disturbing the rotational mounting of the rake structure, to render the diameter of the annular thrust bearing independent of the diameter of the gear, to provide a construction whereby the production cost of the machine is relatively reduced and the erection relatively facilitated, and to provide readily available extra platform working space with extra accessibility to the pinion drive units preferably from all sides.

To obtain the foregoing objectives, the invention provides a drive head featuring a top structure or platform member at the top overhanging an externally toothed bull gear connected to the rake structure and driven by one or more pinion drive units carried by the overhanging portion of the platform member. A turntable base carries the platform member fixed thereto,

while the rake structure is rotatable thereon through an annular vertical thrust bearing surrounded by the gear.

In that construction, the diameter of the annular thrust bearing may be held to a desirable minimum, while allowing the pitch diameter of the surrounding gear to be chosen as large as may be desirable for absorbing the driving torque from the pinion drives. In a preferred embodiment the rotary structure comprises a rim member or annular member rotatable on the thrust bearing, and having fastened thereto the depending center cage of the rake structure, and the aforementioned externally toothed gear, allowing the gear to be mounted or dismounted without disturbing the rotational mounting of the rake structure.

Fastened to the underside of the overhanging portion of the top structure there may be provided a depending detachable annular oil trough structure surrounding the externally toothed portion of the gear, with the bull gear thus easily accessible for inspection or replacement.

The improved drive head construction may be readily combined with rake lifting means for enabling the raking apparatus to handle situations of undue sludge accumulation or overloads, without necessitating any changes insaid improved construction.

Other features and advantages will hereinafter appear.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims, or of forms that are their functional as well as conjointly cooperative equivalents, are therefore intended to be embraced by those claims.

In the attached drawings:

FIG. 1 is a diagrammatic vertical sectional view of settling tank of the general type embodying the invention.

FIG. 1a is a somewhat enlarged view similar to FIG. 1 more detailed.

FIG. 2 is a greatly enlarged vertical sectional detail view of the central portion of the rake structure showing the improved drive head construction, featuring a detachable externally toothed bull gear, and drive units supported from a stationary overhanging top structure, also showing optional rake lifting devices.

FIG. 2a is a greatly enlarged detail view of the annular ball bearing for the rake structure.

FIG. 2b is a detail cross-sectional view taken on line 2b-2b of the vertical guide means associated with the rake lifting device.

FIG. 20 is a detail view of a modified drive pinion mounting differing from the one in FIG. 2.

FIG. 3 is a plan view upon the drive head taken on line 33 in FIG. 2, with interbalanced pinion drive units for the gear.

FIG. 4 is a top view of a modified form of the invention.

FIG. 5 is an enlarged vertical sectional view of the drive head equipped with separate anti-friction bearings for vertical load and radial guidance respectively, as well as with inner and outer concentric annular strip sealing means.

HO. 6 is similar to FIG. 5, showing a modified sealing arrangement including an inner strip seal and an outer liquid seal.

PK]. 7 shows a further modified sealing arrangement including two concentric liquid sealing means.

- FlG.'8 shows another sealing arrangement including an inner liquid seal and an outer strip seal.

FlG. 9 shows still another sealing arrangement utilizing the liquid body in the tank as a sealing medium.

In the embodiment herein exemplifying the invention a settling tank 10 has a center pier 11 surrounded by the central cage portion 11a of a rake structure 12, having rake arms 12a extending therefrom. When the rake structure is rotated on the pier, the rake arms equipped with the usual inclined plowing blades 14 will convey the sedimentation sludge to an annular sump l5 surrounding the foot end of the pier, whence it may be pumped away as indicated by the discharge conduits 16. An alternate way of sludge removal, not shown, is through a conduit leading from the sump upwardly through the hollow pier and then outwardly via a radial stationary truss construction 17 to the periphery of the tank, in which case sludge pumping equipment is located at the bottom of the hollow pier.

Suspending from the truss construction is a feed conduit 17a for the feed slurry to be delivered into an annular feed trough 17b supported upon the rotary rake structure 12 and rotating therewith.

In the embodiment according to FIG. 2, a hollow center pier in the form of a tubular member 18 is mounted and anchored on the base portion 19 of the tank. A drive head D" for supporting and rotating the rake structure comprises a turntable base T having an annular base plate 20 shown to be resting upon the top end 21 of the hollow pier. ln this embodiment the base plate has depending therefrom and fixed thereto a guide cylinder 22 surrounded by and concentric with the hollow pier l8.

Suitable vertical guide track means are provided effective between the depending guide cylinder and the surrounding pier. In the present example, three vertical guide track members 23 are provided on the tubular guide member equally spaced about the vertical axis of rotation of the rake structure. The tracks are engaged by respective guide lugs 24 mounted in the wall of the hollow pier so they will guide the parts 20 and 22 vertically while secured against rotation when the turntable base T is raised or lowered by means of lifting devices furthermore to be described. Three guide roller units 24a equally spaced about the vertical axis of rotation are provided in addition to the tracks for stabilizing the lower end portion of guide cylinder 22.

The base plate 20 has an upright cylindrical portion 25 surrounded at its foot end portion by an annular bearing unit 26 (see also detail HO. 4) supporting the rake structure. This is a combination bearing unit designed for sustaining vertical thrust as well as radial load, comprising an inner annular bearing race 27 seated on should 28 and fitted over the cylindrical face 29 on the turntable base, an outer bearing race 30, and anti-friction elements 31 held in a cage member 38a between the bearing races. This bearing unit is located in an oil trough 32 having an outer upstanding wall 33 formed on base plate 20 of the turntable construction.

Seated upon and fitted over the outer bearing race is an annular rim member or annular member 34. In

this embodiment, the member 34 is of inverted U- shaped cross-sectional configuration having an inner leg 34a and an outer leg 34b. Actually the inner leg is a vertical cylindrical wall portion resting upon bearing 26, while the outer leg is shown as a steeply conically shaped wall portion, both rigidly interconnected by a horizontal annular top portion 34c and reinforced by internal radial ribs 34d. The leg portion 341) has a downward extension 34e to which is fastened the rake structure thus to be supported for rotation upon the aforementioned annular bearing unit 26. The annular member 34 also has an outwardly extending horizontal flange 35 to which is bolted an externally toothed annular bull gear 36 preferably consisting of arcuate component sections concentric with the bearing unit 26.

A horizontal top structure or platform construction 37 is mounted on the inwardly directed horizontal top flange 38 formed on the cylindrical portion 25 of the turntable base. The top structure 37 provides an overhang above the bull gear 36, extending outwardly far enough to have mounted thereon the motor-powered V pinion drive unit 40 having a vertical pinion shaft 40a and pinion 40b in driving engagement with the gear. Worm drive means 400 (see also FIG. 3) in this drive unit have driving connection with the pinion shaft.

Two such pinion drive units 40 may be provided with torque balancing means effective between both drive units to insure that both units will assume equal shares of the total driving torque for the gear.

Such torque balancing means may be of the kind disclosed in the U.S. Fat. to SCOTT No. 2,855,101. Accordingly, the respective worm shaft members 40d in the respective drive units may be interconnected by a coaxial shaft 40f indicated in dot-and-dash. This shaft assembly as a whole acting as a single shaft and driven by motor 40g, is axially slideable in the drive units, so it will axially adjust itself to a position where both drive units will assume equal share of the total driving torque.

Fastened peripherally to the overhanging portion of top structure 37 is a depending oil trough structure 37a surrounding the externally toothed portion of the gear as well as the drive pinions 40b. This trough structure may be detached from the top plate and lowered (see dot-and-dash line position) to expose the bull gear and the pinions for inspection or replacement. Also, the top structure 37 may be detached and raised from the top end of cylindrical portion 25 of the turntable base. The outer wail of the trough structure may have one or more openings 0 closed by detachable cover plates P, through which the gear and drive pinions may be inspected while in operation.

The lower end of the drive pinion shaft may have a bearing 37b provided in the bottom of trough structure 370. A modification of the mounting of the pinion shaft in detail FlG. 5 omits such a bottom bearing in the trough structure.

in FIG. 3, extensions 370 of the overhang of top structure 37 provide added platform area allowing an operator convenient access to the pinion drive units from all sides. I

Means for raising and lowering the rake structure may be provided, comprising a vertical composite column construction 42 fixed to and rising from the bottom 18a of the hollow center pier, within the tubular guide member 22 and through the central opening C" in drive head D, to a height sufficient to allow for the desired lifting stroke H by a jack device mounted atop the column construction 42.

The column construction 42 in this example comprises three vertical tube members in triangular arrangcment, connected together to constitute a rigid stationary tower structure. A platform means 44 at the top constitutes part of this rigid tower structure, and supports the rake lifting mechanism proper here shown to comprise a jack device 45 driven by a reversible motor 46. The jack device supports a horizontal triangular yoke member J of substantially triangular configuration (see FIG. 3), with suspension rods 48 extending downwardly from the respective corners of the yoke member, and having lower threaded end portions fastened or anchored to the top flange 38 of the turntable base, as indicated by nuts 48a.

The top structure 37 presents a convenient working platform of ample size providing convenient access from all sides for mounting, inspecting and servicing the pinion drive units 40. Also from this platform, access may be had through the central opening C to the interior of the tubular guide member 22 and to the interior of the pier and to the vertical track guide facilities therein. The available working platform area may have any suitable peripheral shape surrounded by a railing.

According to one modification (see FIG. 4), the spur gear drive elements, namely the bull gear and the drive pinions, may be replacedby a chain drive arrangement. In such an arrangement, a correspondingly large main sprocket 50 replace the bull gear 36, while correspondingly smaller drive sprockets replace the drive pinions 40b. An endless sprocket chain 53 surrounds and engages the main sprocket 50 and the drive sprockets SI and 52.

The two sprocket drive units may be torquebalaneed relative to each other, that is substantially in the manner described in connection with FIG. 3 above.

In summary, it will be seen that the invention provides important novel features and advantages with respect to construction, erection, operation, and servicing of the machine, as well as with respect to flexibility of design.

The rotary assembly above set forth provides flexibility of design with respect to independent optimum dimensioning of the thrust bearing and the gear, while allowing for the gear to be mounted or replaced without disturbance of the rotational support of the rake structure. Flexibility is also provided with respect to the optional inclusion of the rake lifting devices. The bull gear and the drive pinions are readily accessible for inspection or replacement when the depending trough member is lowered, while servicing and inspection of the drive units, and potentially also of the rake lifting devices, may be carried out conveniently from the extra available platform space. Manufacturing and erection procedures are facilitated for instance by the external tooth cutting operation on the bull gear and by the independent mounting on the rim member. In case rake lifting devices are included, the jack device after disconnecting from the turntable base may be employed either for lowering the depending trough structure 370, or for raising the top plate 37 when disconnccted from the turntable base.

The enlarged view of the drive head in FIG. 5 differs from the one in FIG. 2 mainly by the provision of a separate vertical annular thrust bearing 53 associated with a separate radial guide bearing 54 both bearings being shown as of the antifriction roller type. Consequently, an annular member 55 which is part of the rotary rake structure, is supported and guided by these antifriction bearings upon a turntable base structure 56 which is generally similar to the one in FIG. 2. Similarly also is a top structure 57 bolted to the base structure supporting a drive unit 58 which has a drive pinion 59 engaging an externally toothed bull gear 60 mounted upon external flange 61 of annular member 55. The pinion and the bull gear are surrounded by an annular trough 62 containing lubricating oil for the gears.

The turntable base structure is mounted upon, and supported by a ring member 63 of T-shaped cross-section, which in turn fits over and is fastened to the top end of a cylindrical center pier column K.

In addition, this embodiment is provided with two annular concentric sealing devices 64 and 65. The inner sealing device 64 closes the gap G-l between the stationary turntable base and an inner flange 66 of the rotary annular member 55. In this device an annular strip of felt 64a or other suitable sealing material is seated in an annular channel 67 which has a flange 68 fastened to ring member 63.

The outer sealing device comprises an annular strip 69 of sealing material seated in an annular channel 69 provided upon the inner cylindrical wall 70 of trough 62. The strip 69 sealingly engages the underside of a flange 61 formed on annular member 55 thus closing the annular gap G-2 between the rotary annular member and the stationary trough.

In this way, the drive head may be pre-assembled as a unit including the ring member 63. A thus prepared sealed unit shipped to the construction site, may be fitted over the top end of the center pier column K, and secured in place.

The construction in FIG. 6 is substantially identical to that of FIG. 5, except in that the outer annular sealing device 72 is of the liquid sealing type comprising a cylindrical skirt 73 depending from trough 62 into an annular channel 73a containing a sealing liquid such as oil.

In the embodiment of FIG. 7 both the inner sealing device 74 and the outer sealing device 75 are of the liquid sealing type. The inner sealing device 74 has an annular channel 76 depending from the periphery of stationary ring member 63, and a cylindrical member or skirt 76a depending into the channel from an internal flange 77 of annular member 55. A horizontal oil level indicator pipe 78 extends from channel 74 through the wall of center pier column K.

The outer sealing device 75 has an annular channel 79 extending exteriorly along the periphery of the lower cylindrical part 79a of annular member 55, and cooperating with a skirt 80 depending from annular trough 62 which is similar to that of FIGS. 5 and 6.

The embodiment in FIG. 8 is similar to FIG. 7 in respect to the provision of the inner annular liquid seal 74 with oil level indicator pipe, whereas the outer annular seal 81 employs a sealing strip 82 of suitable flexible material fastened to a skirt 83 depending from trough 62, and engaging a shelf 84 provided upon the rotating annular member 55.

The embodiment in FIG. 9 again is structurally similar to FIG. 1, although provided with a different sealing system. In this showing instead of providing individual seals for gaps G-1 and 6-2, a skirt 85 depending from trough 62 into the liquid body B in the tank provides a common seal for both gaps. However, it will be understood that this common seal utilizing the tank contents as the liquid sealing medium, is applicable in addition to, or in combination with any of the other sealing devices or combinations of sealing devices above described.

It will be understood that each of the elements, or I two or more together, may also find useful application in other types of apparatus having a rake structure suptank, said settling tank having a base portion, the combination which comprises a rotary sediment engaging structure rotatable about a vertical axis and provided with a central vertical cage portion having an annular member connected to the cage portion at the upper end thereof, an externally toothed gear connected to said annular member concentric with said axis of rotation, upright support structure fixed to said base portion of the tank, extending upwardly within said cage portion, a turntable base structure for rotatably supporting said sediment engaging structure, said turntable structure being supported on said upright support structure while secured against rotation, and comprising an annular bottom portion and an upright inner peripheral extension, annular bearing means mounted on said bottom portion of the turntable base structure for rotatably supported said annular member and the sediment engaging structure and the gear connected thereto, a top structure fixed to the upper end of said upright extension of the turntable structure and extending outwardly therefrom a distance substantially beyond the maximum radius of the gear, and drive means comprising a drive unit mounted on said outwardly extending top structure, for rotating said gear and said sediment engaging structure.

2. The sedimentation apparatus according to claim 1, wherein said upright support structure comprises a pier construction directly supporting said turntable structure.

3. The sedimentation apparatus according to claim 1, wherein said upright support structure comprises a hollow tubular member substantially coaxial with said axis of rotation, directly support said turntable structure.

4. The sedimentation apparatus according to claim 1, wherein said upright support structure comprises a support column construction extending to a height a substantial distance above said top structure, and actuating means connecting the top end of said support column with said turntable structure, and operable for raising and lowering the same together with the sediment engaging structure, with the addition of vertical guide means for vertically guiding said turntable base structure while securing the same against rotation.

5. The sedimentation apparatus according to claim 4,

wherein said support column construction comprises a plurality of vertical parallel pole elements and means for interconnecting them to provide a rigid vertical cage structure, said interconnecting means comprising a platform structure at the top end of said pole elements, and wherein said actuating means comprise a jack device mounted-on said platform structure, a crosshead supported from below by said jack device, and vertical suspension member connecting said crosshead with said turntable structure for raising and lowering the same by the operation of said jack device.

6. Sedimentation apparatus according to claim 1, wherein at least a pair of drive units are mounted on said top plate structure opposite to one another, and torque balancing means are provided operatively interconnecting said drive units, whereby equal drive torque load is imposedupon each said drive unit. I

7. Sedimentation apparatus according to claim 6, wherein said gear is a spur gear, and said drive units each have a drive pinion in driving engagement with said gear.

8. Sedimentation apparatus according to claim 6, wherein said gear is in the form of a driven sprocket, wherein said drive units each have a drive sprocket, and an endless drive chain is provided surrounding said driven sprocket and said drive sprockets in operative engagement therewith for imparting balanced drive torque from said drive sprockets to said driven sprocket and to the sediment engaging structure connected thereto.

9. Sedimentation apparatus according to claim 1, wherein said top structure extends a substantial distance beyond and around said drive unit, providing operating platform area therefor.

10. Sedimentation apparatus according to claim 1, wherein said gear is a spur gear having an inner rim portion and an outer depending toothed portion, wherein said top structure extends over the area of said gear, and wherein there is provided a substantially annular trough structure substantially enclosing said depending toothed gear portion, said trough structure having an outer wall detachably connected to said top structure.

11. Sedimentation apparatus according to claim I0, wherein said drive unit comprises a vertical shaft extending through said top structure, with bearing means for the lower end of said shaft provided in the bottom of said trough structure.

12. Sedimentation apparatus according to claim 10, wherein said outer wall of the trough structure has an inspection opening and detachable closure means therefor.

13. In a sedimentation apparatus having a settling tank, said settling tank having a base portion, the combination which comprises a rotary sediment engaging structure rotatable about a vertical axis and provided with a central vertical cage portion; an annular member fixed to said cage portion concentric therewith, said annular member being of inverted U-shaped cross-sectional configuration, said cage portion being connected to the outer leg of said inverted U-shape; an externally toothed gear detachable connected to said outer leg, concentric with said axis of rotation; upright support structure fixed to said base portion, extending upwardly within said cage portion; a turntable base for rotatably supporting said sediment engaging structure, and supported on said upright support structure while secured against rotation, said turntable base comprising an annular bottom portion and an upright inner peripheral extension; an annular trough formed around said upright extension; annular bearing means mounted in said trough concentric with said axis of rotation, for rotatably supporting the inner leg of said inverted U- shape and thus the sediment engaging structure and the gear connected thereto; a top structure fixed to the upper end of said upright extension of the turntable base and extending outwardly and overhanging said gear; and drive means comprising a drive unit mounted on said top structure, for rotating said gear and'said sediment engaging structure.

14. The apparatus according to claim 1, wherein said annular member extends inwardly from said cage portion and inwardly from said gear.

15. In a sedimentation apparatus having a settling tank, said tank having a base portion, the combination which comprises a rotary sediment engaging structure rotatable about a vertical axis and provided with a central vertical cage portion, an annular member connected to the cage portion at the upper end thereof, an externally toothed gear connected to said annular member concentric with said axis of rotation, upright support structure fixed to said base portion of the tank, extending upwardly within said cage portion, a turntable base structure for rotatably supporting said sediment engaging structure, said turntable structure being supported on said upright support structure while secured against rotation, and comprising an annular bottom portion and an upright inner peripheral extension, annular bearing means mounted on said bottom portion of the turntable base structure for rotatably supporting said annular member and the sediment engaging structure and the gear connected thereto, a top structure fixed to the upper end of said upright extension of the turntable structure and extending outwardly therefrom a distance substantially beyond the maximum radius of the gear, and drive means for said gear including a rotary drive element for said gear rotatably mounted in the outwardly extending portion of said top structure.

16. The combination according to claim 15, wherein said gear has a depending toothed portion, with the addition of a substantially annular trough structure substantially enclosing said depending toothed gear portion, and having an outer wall detachably connected to said top structure.

17. The apparatus according to claim 15, wherein said annular bearing means comprise a vertical thrust bearing means having a pair of bearing races and antifriction bearing elements therebetween, and radial guide bearing means effective between said annular member and said upright inner peripheral extension of the turntable base structure.

18. The apparatus according to claim 15, wherein said annular bearing means comprise a vertical thrust bearing mean having a pair of bearing races and antifriction bearing elements therebetween, and radial guide bearing means having a pair of cylindrical concentric bearing races and antifriction bearing elements therebetween. I

19. The apparatus according to claim 15, wherein said gear has a depending toothed portion, with the addition of a substantially annular trough structure substantially enclosing said depending gear portion, and having an outer wall connected to said top structure, and wherein there are provided two concentric annular sealing devices, namely an inner sealing device effective between said annular member and said bottom portion of the turntable base structure, and outer sealing device effective between said annular member and the surrounding trough structure.

20. The apparatus according to claim 19, wherein each of the sealing devices comprise an annular sealing strip.

21. The apparatus according to claim 19, wherein one sealing device comprises an annular sealing strip, and the other sealing device comprises an annular liquid seal.

22. The apparatus according to claim 19, wherein each of the sealing devices comprises an annular liquid seal.

23. The apparatus according to claim 19, wherein the outer sealing device comprises an annular channel surrounding said annular member connected thereto, and a cylindrical skirt depending from said trough into said annular channel.

24. The apparatus according to claim 19, wherein the inner sealing device comprises an annular channel surrounding said turntable base, an inwardly directed annular shelf extending along the interior periphery of said annular member, and a cylindrical skirt depending from said annular shelf into said annular channel.

25. The apparatus according to claim 15, wherein said gear has a depending toothed portion, with the addition of a substantially annular trough structure substantially enclosing said depending gear portion, and having an outer wall portion connected to said top structure, with the addition of a cylindrical shroud extending downwardly from said trough structure substantially concentric therewith, and having a lower end portion immersed in the liquid in the tank, thereby providing a sealing means for said bearing means as well as for said gear in said trough.

26. The apparatus according to claim 13, wherein said bearing means comprise an annular vertical load carrying antifriction bearing supporting said inner leg of the inverted U-shape, and an annular radial antifriction bearing effective between said upright extension and the surrounding inner leg of said inverted U-shape.

27. The apparatus according to claim 26, wherein at least one of said load carrying and radial antifriction bearings is a roller bearing.

28. The apparatus according to claim 13, wherein said gear is a spur gear having an inner rim portion and an outer depending toothed portion, and wherein there is provided a substantially annular trough structure substantially enclosing said depending tooth gear portion, said trough structure having an outer wall detachably connected to said top structure.

29. Sedimentation apparatus according to claim 15, wherein at least a pair of rotary drive elements are and an endless drive chain is provided surrounding said driven sprocket and said drive, sprockets in operative engagement therewith for imparting balanced drive torque from said drive sprockets to said driven sprocket and to the sediment engaging structure connected thereto.

32. Sedimentation apparatus according to claim 15, wherein said top structure extends a substantial distance beyond and around said drive element providing operating platform area therefor. 

1. In a sedimentation apparatus having a settling tank, said settling tank having a base portion, the combination which comprises a rotary sediment engaging structure rotatable about a vertical axis and provided with a central vertical cage portion having an annular member connected to the cage portion at the upper end thereof, an externally toothed gear connected to said annular member concentric with said axis of rotation, upright support structure fixed to said base portion of the tank, extending upwardly within said cage portion, a turntable base structure for rotatably supporting said sediment engaging structure, said turntable structure being supported on said upright support structure while secured against rotation, and comprising an annular bottom portion and an upright inner peripheral extension, annular bearing means mounted on said bottom portion of the turntable base structure for rotatably supported said annular member and the sediment engaging structure and the gear connected thereto, a top structure fixed to the upper end of said upright extension of the turntable structure and extending outwardly therefrom a distance substantially beyond the maximum radius of the gear, and drive means comprising a drive unit mounted on said outwardly extending top structure, for rotating said gear and said sediment engaging structure.
 2. The sedimentation apparatus according to claim 1, wherein said upright support structure comprIses a pier construction directly supporting said turntable structure.
 3. The sedimentation apparatus according to claim 1, wherein said upright support structure comprises a hollow tubular member substantially coaxial with said axis of rotation, directly support said turntable structure.
 4. The sedimentation apparatus according to claim 1, wherein said upright support structure comprises a support column construction extending to a height a substantial distance above said top structure, and actuating means connecting the top end of said support column with said turntable structure, and operable for raising and lowering the same together with the sediment engaging structure, with the addition of vertical guide means for vertically guiding said turntable base structure while securing the same against rotation.
 5. The sedimentation apparatus according to claim 4, wherein said support column construction comprises a plurality of vertical parallel pole elements and means for interconnecting them to provide a rigid vertical cage structure, said interconnecting means comprising a platform structure at the top end of said pole elements, and wherein said actuating means comprise a jack device mounted on said platform structure, a crosshead supported from below by said jack device, and vertical suspension member connecting said crosshead with said turntable structure for raising and lowering the same by the operation of said jack device.
 6. Sedimentation apparatus according to claim 1, wherein at least a pair of drive units are mounted on said top plate structure opposite to one another, and torque balancing means are provided operatively interconnecting said drive units, whereby equal drive torque load is imposed upon each said drive unit.
 7. Sedimentation apparatus according to claim 6, wherein said gear is a spur gear, and said drive units each have a drive pinion in driving engagement with said gear.
 8. Sedimentation apparatus according to claim 6, wherein said gear is in the form of a driven sprocket, wherein said drive units each have a drive sprocket, and an endless drive chain is provided surrounding said driven sprocket and said drive sprockets in operative engagement therewith for imparting balanced drive torque from said drive sprockets to said driven sprocket and to the sediment engaging structure connected thereto.
 9. Sedimentation apparatus according to claim 1, wherein said top structure extends a substantial distance beyond and around said drive unit, providing operating platform area therefor.
 10. Sedimentation apparatus according to claim 1, wherein said gear is a spur gear having an inner rim portion and an outer depending toothed portion, wherein said top structure extends over the area of said gear, and wherein there is provided a substantially annular trough structure substantially enclosing said depending toothed gear portion, said trough structure having an outer wall detachably connected to said top structure.
 11. Sedimentation apparatus according to claim 10, wherein said drive unit comprises a vertical shaft extending through said top structure, with bearing means for the lower end of said shaft provided in the bottom of said trough structure.
 12. Sedimentation apparatus according to claim 10, wherein said outer wall of the trough structure has an inspection opening and detachable closure means therefor.
 13. In a sedimentation apparatus having a settling tank, said settling tank having a base portion, the combination which comprises a rotary sediment engaging structure rotatable about a vertical axis and provided with a central vertical cage portion; an annular member fixed to said cage portion concentric therewith, said annular member being of inverted U-shaped cross-sectional configuration, said cage portion being connected to the outer leg of said inverted U-shape; an externally toothed gear detachable connected to said outer leg, concentric with said axis of rotation; upright support structure fixed to said base portIon, extending upwardly within said cage portion; a turntable base for rotatably supporting said sediment engaging structure, and supported on said upright support structure while secured against rotation, said turntable base comprising an annular bottom portion and an upright inner peripheral extension; an annular trough formed around said upright extension; annular bearing means mounted in said trough concentric with said axis of rotation, for rotatably supporting the inner leg of said inverted U-shape and thus the sediment engaging structure and the gear connected thereto; a top structure fixed to the upper end of said upright extension of the turntable base and extending outwardly and overhanging said gear; and drive means comprising a drive unit mounted on said top structure, for rotating said gear and said sediment engaging structure.
 14. The apparatus according to claim 1, wherein said annular member extends inwardly from said cage portion and inwardly from said gear.
 15. In a sedimentation apparatus having a settling tank, said tank having a base portion, the combination which comprises a rotary sediment engaging structure rotatable about a vertical axis and provided with a central vertical cage portion, an annular member connected to the cage portion at the upper end thereof, an externally toothed gear connected to said annular member concentric with said axis of rotation, upright support structure fixed to said base portion of the tank, extending upwardly within said cage portion, a turntable base structure for rotatably supporting said sediment engaging structure, said turntable structure being supported on said upright support structure while secured against rotation, and comprising an annular bottom portion and an upright inner peripheral extension, annular bearing means mounted on said bottom portion of the turntable base structure for rotatably supporting said annular member and the sediment engaging structure and the gear connected thereto, a top structure fixed to the upper end of said upright extension of the turntable structure and extending outwardly therefrom a distance substantially beyond the maximum radius of the gear, and drive means for said gear including a rotary drive element for said gear rotatably mounted in the outwardly extending portion of said top structure.
 16. The combination according to claim 15, wherein said gear has a depending toothed portion, with the addition of a substantially annular trough structure substantially enclosing said depending toothed gear portion, and having an outer wall detachably connected to said top structure.
 17. The apparatus according to claim 15, wherein said annular bearing means comprise a vertical thrust bearing means having a pair of bearing races and anti-friction bearing elements therebetween, and radial guide bearing means effective between said annular member and said upright inner peripheral extension of the turntable base structure.
 18. The apparatus according to claim 15, wherein said annular bearing means comprise a vertical thrust bearing mean having a pair of bearing races and antifriction bearing elements therebetween, and radial guide bearing means having a pair of cylindrical concentric bearing races and antifriction bearing elements therebetween.
 19. The apparatus according to claim 15, wherein said gear has a depending toothed portion, with the addition of a substantially annular trough structure substantially enclosing said depending gear portion, and having an outer wall connected to said top structure, and wherein there are provided two concentric annular sealing devices, namely an inner sealing device effective between said annular member and said bottom portion of the turntable base structure, and outer sealing device effective between said annular member and the surrounding trough structure.
 20. The apparatus according to claim 19, wherein each of the sealing devices comprise an annular sealing strip.
 21. The apparatus according to claim 19, wherein one sealIng device comprises an annular sealing strip, and the other sealing device comprises an annular liquid seal.
 22. The apparatus according to claim 19, wherein each of the sealing devices comprises an annular liquid seal.
 23. The apparatus according to claim 19, wherein the outer sealing device comprises an annular channel surrounding said annular member connected thereto, and a cylindrical skirt depending from said trough into said annular channel.
 24. The apparatus according to claim 19, wherein the inner sealing device comprises an annular channel surrounding said turntable base, an inwardly directed annular shelf extending along the interior periphery of said annular member, and a cylindrical skirt depending from said annular shelf into said annular channel.
 25. The apparatus according to claim 15, wherein said gear has a depending toothed portion, with the addition of a substantially annular trough structure substantially enclosing said depending gear portion, and having an outer wall portion connected to said top structure, with the addition of a cylindrical shroud extending downwardly from said trough structure substantially concentric therewith, and having a lower end portion immersed in the liquid in the tank, thereby providing a sealing means for said bearing means as well as for said gear in said trough.
 26. The apparatus according to claim 13, wherein said bearing means comprise an annular vertical load carrying antifriction bearing supporting said inner leg of the inverted U-shape, and an annular radial antifriction bearing effective between said upright extension and the surrounding inner leg of said inverted U-shape.
 27. The apparatus according to claim 26, wherein at least one of said load carrying and radial antifriction bearings is a roller bearing.
 28. The apparatus according to claim 13, wherein said gear is a spur gear having an inner rim portion and an outer depending toothed portion, and wherein there is provided a substantially annular trough structure substantially enclosing said depending tooth gear portion, said trough structure having an outer wall detachably connected to said top structure.
 29. Sedimentation apparatus according to claim 15, wherein at least a pair of rotary drive elements are mounted on said top plate structure opposite to one another, and torque balancing means are provided operatively interconnecting said drive elements, whereby equal drive torque load is imposed upon each said drive element.
 30. Sedimentation apparatus according to claim 29, wherein said gear is a spur gear, and said drive elements each have a drive pinion in driving engagement with said gear.
 31. Sedimentation apparatus according to claim 29, wherein said gear is in the form of a driven sprocket, wherein each said drive element is a drive sprocket, and an endless drive chain is provided surrounding said driven sprocket and said drive sprockets in operative engagement therewith for imparting balanced drive torque from said drive sprockets to said driven sprocket and to the sediment engaging structure connected thereto.
 32. Sedimentation apparatus according to claim 15, wherein said top structure extends a substantial distance beyond and around said drive element providing operating platform area therefor. 